The present invention generally relates to rotary connectors, and more particularly, to an improved rotary connector comprising rotatable insulating members having conductive rings electrically interconnected with rolling conductive members. A second embodiment of the present invention provides for a rotary connector that employs ball contacts that make electrical contact with conductive rings comprising plated V- or U-shaped grooves disposed on printed wiring boards. By creating plated grooves (V or U shape) on the surface of the printed wiring boards, the balls rotate on edges the grooves. The contact area between the ball and conductors on the printed wiring boards is increased by four fold from a design where the balls contact flat tracks or conductors of the printed wiring board, such as in the first embodiment of the present invention.
Two or more identical conductive rings formed by chemical or mechanical processes on electrically isolated materials, such as on the printed wiring boards, are connected using a rolling conductive member such as a stainless steel ball or a multiplicity of conductive balls (or rollers), for example. The design of the groove-shaped conductors is such that their surfaces provide for smooth rolling of the balls. The rotary connector has an isolating spacer, a shaft and a means for maintaining pressure between the conductors and the balls when the conductors move relative to one another.
The present invention allows construction of rotating connectors having several electrical signals transmitted from a stationary source to moving parts with minimum contact resistance. A rolling motion dissipates only 1/10th the amount of energy of friction-type motion. This means that the rolling ball connector can perform at higher speeds for a longer lifetime and at lower cost.
Prior art relating to the present invention include slip ring devices and cable wrap assemblies. The disadvantages of slip ring devices and cable wrap assemblies are that they are bulky, heavy, difficult or impossible to repair, very expensive, and brush or solder joints used therein often fail during operation. More specifically, conventional slip ring connectors, for example, are very fragile device. In harsh environments, such slip ring connectors often fail due to the fragile nature of brushes and rings used therein. Complicated bulky cable wrap assemblies are typically used to permit multiple electrical signals to be transmitted from a stationary source to a moving component. The cable wrap assemblies have many field-related problems such as wear and tear, decomposition of solder joints, and the like.
Therefore, it is an objective of the present invention to provide for a rotary connector comprising rotatable insulating members having conductive rings electrically interconnected with rolling conductive members that improves over conventional slip ring devices and cable wrap assemblies.